Why Do "Tails" Appear On Some Of My Moho Character

Bee-ruce · Post by **Bee-ruce** » Fri Dec 16, 2005 6:24 pm

Hi. I've had about 3 occasions where "tails" have appeared on a bone-rigged character. By "tails" I mean a long thick line or "rod" of whatever color the character is in attached to the character and protruding outwards.If I play back the segment within Moho it looks fine however if I export the segment.....the "tails" appear. Appreciate if anyone can tell me why they appear and how to get rid of them.Thanks

Rasheed · Post by **Rasheed** » Fri Dec 16, 2005 7:33 pm

Was that animating rigged image layers or rigged vector layers? Can you show us a screenshot, so we know what you are writing about?

Bee-ruce · Post by **Bee-ruce** » Fri Dec 16, 2005 8:44 pm

Hi. I'm talking about rigged image layers.I'd be happy to show a screenshot however not sure how to add one to this forum post.

Rasheed · Post by **Rasheed** » Fri Dec 16, 2005 9:15 pm

http://www.imageshack.us/

Bee-ruce · Post by **Bee-ruce** » Fri Dec 16, 2005 10:07 pm

Hope this helps. It shows 2 tails coming off the girls arms and a couple tails underneath the boys arm.

Rasheed · Post by **Rasheed** » Fri Dec 16, 2005 10:46 pm

I could be that you used region binding instead of flexible binding. Region binding can sometime give unwanted distortions.

Region binding

Flexible binding

Both files in this example are the same, except for the type of bone binding. You can change the bone binding by double clicking the bone layer(s), select the bone tab, select the Flexible binding radio button and click the OK button.

See if this might help.

Post by **Lost Marble** » Sat Dec 17, 2005 2:15 am

In region binding, if part of the image is outside all the bones' regions of influence, it will move with the nearest bone. The nearest bone may not be the one you want. In this case, it may be that part of the arm moved with a leg bone. Use the Bone Strength tool to see and adjust the regions of influence for the bones.

With flexible binding, the transition from one bone to the next remains smooth. The downside is that you can get situations where characters look too "rubbery".

Rasheed · Post by **Rasheed** » Sat Dec 17, 2005 12:29 pm

Lost Marble wrote:Use the Bone Strength tool to see and adjust the regions of influence for the bones.

I have noticed that the visual representation of bone strengh on image layers is somewhat different than the actual reach of a bone. You would expect the influence not to go beyond the colored area. In my experience, however, you can easily double the surface area you see on screen, as far as the influence of a single bone's strength is concerned.

Lost Marble wrote:With flexible binding, the transition from one bone to the next remains smooth. The downside is that you can get situations where characters look too "rubbery".

I have experimented somewhat with flexible binding and bone offset. It seems the more bone offset you use, the less "rubbery" the animation gets. I guess the "rubberiness" comes from the influence by other bones on the warping of an image layer.

I will try to create some examples of that and put it on the Moho Reference wiki.

Please strike this, because in honesty, I can't really claim that (yet, I haven't tested it enough):
" It seems the more bone offset you use, the less "rubbery" the animation gets. I guess the "rubberiness" comes from the influence by other bones on the warping of an image layer."

Bee-ruce · Post by **Bee-ruce** » Sat Dec 17, 2005 3:14 pm

Thanks for the suggestions....I'll try making some adjustments.

Rasheed · Post by **Rasheed** » Sun Dec 18, 2005 4:14 pm

I hope that works, Bee-ruce.

In the mean time I have been working on my article. It isn't finished, but I want you to know what I discovered until now.

I made a rather simple animation with several image layers of a little jumping girl:

I used the following settings (show one after another in the movie):
1. images on top of eachother, region binding, bone strength 1
2. images on top of eachother, region binding, bone strength 0.00001
3. images on top of eachother, flexible binding, bone strength 0.00001
4. images on top of eachother, flexible binding, bone strengh 1
5. images spread far apart, flexible binding, bone strength 0.00001
6. images spread far apart, region binding, bone strength 0.00001
7. images spread far apart, flexible binding, bone strength 1
8. images spread far apart, region binding, bone strength 1

1 is the worst result, then 2, then 3 and then 4. The difference in quality between 5 through 8 is small, but 6 is better than 5 and 7 is better than 6. I couldn't find any difference between 7 and 8, so they are both the best result.

You could argue that one would prefer 3 or 4, because when you spread the legs, the dress automatically widens. However, look what happens with the hair; that can't be right. Furthermore, you can add extra bones on the dress to widen it:

So, for this particular animation, it seems that putting as much space as possible between the image layers is a good thing, as well as setting the bone strength at a normal value. Then it doesn't matter what kind of binding you use.

At least in this animation. I want to create some more examples to see if there are cases where one might prefer one type of bone binding over another.